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What your calcium score means

The Agatston score measures calcified plaque in your coronary arteries. How the number is built, what each band describes, and what it cannot describe.

A coronary artery calcium scan produces a single number: the Agatston score. It is calculated from the area and density of calcified plaque visible in your coronary arteries on a non-contrast CT.

That is the whole measurement. It is a plaque-burden number. It is not a picture of a blockage, it does not tell you whether an artery is narrowed, and it cannot see non-calcified plaque. A mention of coronary calcium on a routine chest CT is a related but different report (calcium on a chest CT).

Nobody has medically reviewed this page. CalciumCT.com is a directory of published cash prices. We do not perform scans, read scans, employ clinicians, or practice medicine in any state. Everything below is sourced and linked so you can check it yourself, and none of it is advice about you. How our guides are written.

How the number is actually built

The Agatston score is not a volume, a percentage or a probability. Scoring software finds every area of calcification in the coronary arteries that is denser than 130 Hounsfield units and covers at least 1 mm² — three adjacent pixels. Each of those lesions is measured by area, then multiplied by a density factor: 1 for a peak density of 130–199 HU, 2 for 200–299, 3 for 300–399, and 4 for 400 and above. Every lesion’s result is added up. That total is your number. (Agatston’s method, described in an open-access review; originally Agatston AS, Janowitz WR, et al., Journal of the American College of Cardiology, 1990.)

Two things follow from that arithmetic, and both matter when people compare numbers:

The bands

  1. 0

    No identifiable calcified plaque. Does not rule out all coronary disease.

    A zero does not mean zero risk. The scan only sees calcified plaque, and non-calcified plaque does not show up. Interpret this result alongside your other risk factors with your clinician.

  2. 1–10

    Minimal calcified plaque. Discuss the result with your clinician.

    A small amount of calcified plaque is present. Even a low positive score is evidence of coronary atherosclerosis; its significance depends on your age and overall risk profile.

  3. 11–100

    Mild plaque. Worth discussing risk-factor modification with your doctor.

    Plaque is established. This is the band where people most often talk with a clinician about blood pressure, lipids, smoking, and family history.

  4. 101–400

    Moderate plaque. Follow up with your doctor on next steps.

    A moderate burden of calcified plaque. Your clinician may want more testing or a change in how aggressively your risk factors are managed.

  5. Over 400

    Extensive plaque. Higher risk. Prompt clinician follow-up.

    A high calcium burden. This is a result to take to a clinician promptly rather than sitting on. It is a measure of plaque, not a diagnosis of a blockage, and what happens next is a decision for you and your doctor.

A calcium score is one data point, not a diagnosis. What it means for you is a conversation with a licensed clinician.

Where those boundaries come from, and why other people’s are different

The labels above — minimal, mild, moderate, extensive — come from a descriptive categorisation published by Rumberger and colleagues in Mayo Clinic Proceedings in 1999 (PMID 10089993). It is one of several ways the same number gets cut up, and the cuts do not agree with one another. MESA’s ten-year outcome analysis, for instance, reports at 0, 1–100, 101–300 and above 300 — its top group opens at 301, ours at 401. Professional guidelines use cut points of their own and attach them to treatment decisions; those are a clinician’s to apply and we do not restate them here.

So the same score can be labelled one way on this page and another way by whoever reads your report. That is a fact about the labelling schemes, not a fact about you, and it is a fair thing to ask about if the two descriptions you have been given do not match.

If your report lists the arteries separately

Some reports give the total only. Others break it down, using abbreviations that are rarely explained:

The Society of Cardiovascular Computed Tomography publishes a standardised reporting system for calcium scans, CAC-DRS. Its own summary describes the classification as applied per patient and representing “the total calcium score and the number of involved arteries” (Hecht HS, et al., Journal of Cardiovascular Computed Tomography, 2018, PMID 29793848).

What a particular vessel’s share of the total means is not something a directory can tell you. It is a good question for the clinician who ordered the scan.

What has been measured alongside these numbers

The largest long-running US study of coronary calcium in people without known heart disease is MESA, the Multi-Ethnic Study of Atherosclerosis. In MESA — 6,814 US adults aged 45 to 84 with no known cardiovascular disease when they enrolled, followed a median of 11.1 years — ten-year event rates among people who scored 0 ranged from 1.3% to 5.6% depending on age, sex and race or ethnicity. Among people who scored above 300 they ranged from 13.1% to 25.6% (Budoff MJ, et al., European Heart Journal, 2018, PMC6030975).

Three things to hold onto about those ranges. They are averages for groups of people, not a prediction about you. Roughly a third of the events counted were strokes, not heart attacks. And everyone in that study was at least 45 when they enrolled, so none of it describes a younger adult.

The bands stop at 400. The gradient does not.

A report of 1,200 is not “the top band” in the way 420 is. A MESA analysis of participants scoring 1,000 or more found risk continuing to rise at the top of the scale rather than levelling off (Peng AW, et al., Circulation, 2021, PMID 33650435). What a very high score means for a particular person is a clinical question and not a directory question, and it is one worth asking soon rather than sitting on.

The raw number and the percentile are two different measures

Your report may also carry a percentile — where your score sits among people of the same age, sex and race or ethnicity. In MESA, researchers compared the two directly for predicting coronary events. Both predicted events strongly. The absolute score predicted them somewhat better. The authors wrote that they “recommend using cut points based on the absolute CAC amount, and the common CAC cut points of 100 and 400 seem to perform well,” and that “patients with low absolute scores are low-risk, regardless of age-, sex-, and race/ethnicity-specific percentile rank” (Budoff MJ, et al., JACC, 2009, PMID 19161884). Two limits worth knowing: that study enrolled nobody under 45, and it followed people for under four years, which is a different question from what a score means over a lifetime.

The short version, if your report carries both: the raw number is the one the evidence supports acting on, and a high percentile attached to a low absolute score is not the alarming combination it looks like. If you want to see where your number actually sits, calcium score by age publishes MESA’s own reference values and the limits they come with.

If your score is zero

A zero is a genuinely strong result and it is not a rule-out. The 2019 ACC/AHA primary prevention guideline says so in its own words:

Note that the absence of coronary artery calcium does not rule out noncalcified plaque, and clinical judgment about risk should prevail.

(Arnett DK, et al., Circulation, 2019;140(11):e596–e646, Section 2.2, PMC7734661.)

The reason is mechanical rather than rhetorical: the scan can only see plaque that has calcified. Soft, non-calcified plaque does not appear on a non-contrast calcium scan at all, and a score of zero says nothing about it.

How strong a result it is. In MESA, researchers compared 13 different reassuring findings to see which one moved a person’s estimated risk down the most. A calcium score of zero moved it down further than any of the others — further than a normal C-reactive protein, a normal ankle-brachial index, or having no family history of coronary heart disease (Blaha MJ, Cainzos-Achirica M, Greenland P, et al., Circulation, 2016, PMID 26801055). Note what that study compared: reassuring findings against one another. It says nothing about how a zero compares with a positive result.

And it is still not none. In a 2009 systematic review, 13 studies followed 64,873 asymptomatic people; among the 25,903 who had no coronary calcium, 146 — 0.56% — had a cardiovascular event over a mean follow-up of about 51 months (Sarwar A, Shaw LJ, Shapiro MD, et al., JACC: Cardiovascular Imaging, 2009, PMID 19520336). Those were people without symptoms, over roughly four and a quarter years on average. Do not let anyone stretch that number into a lifetime.

The same 2019 guideline also tells clinicians not to down-classify risk on a zero score in people who still smoke, have diabetes, have a family history of ASCVD, or have chronic inflammatory conditions — in those groups a zero “does not rule out risk from noncalcified plaque or increased risk of thrombosis” (Section 4.3). That is a statement about how a clinician reads the result, not a rule you apply to yourself. If one of those describes you, it is worth naming when you discuss the result.

What the score does not tell you

A positive score is evidence of coronary atherosclerosis. It does not tell you how much an artery is narrowed. Narrowing is a different question answered by a different test — a CT angiogram, CPT 75574, which uses contrast dye. A stress test asks whether heart muscle is short of blood under strain, and calcium mentioned on a chest CT is a finding on a different scan. If you have seen a claim that a score over 400 means a specific probability that an artery is blocked, that is a misreading: the Agatston score is a weighted sum of calcified lesions, and it does not measure stenosis at all.

It cannot see soft plaque. A 2026 mini-review in Frontiers in Radiology notes that because the score does not detect non-calcified plaque it “may therefore underestimate risk in selected patients, particularly younger individuals or symptomatic patients with early-stage atherosclerosis,” and that a calcium score is not used to rule out obstructive coronary disease in someone who has symptoms (Sabouret P, Giamundo DM, Rosencher J, Figliozzi S, Frontiers in Radiology, 2026).

It is not a test for symptoms you are having now. If you have chest pain, pressure, breathlessness or anything else that worries you, that is a conversation to have with a clinician today, and a calcium score — including a zero — is not the test that answers it. There is a number attached to that, from a population quite different from most readers of this page: among 10,037 symptomatic patients referred for CT angiography in the CONFIRM registry, about half had a calcium score of zero, and of those, 3.5% still had a 50%-or-greater narrowing in a coronary artery (Villines TC, et al., JACC, 2011, PMID 22079127). Those people already had symptoms and had been sent for further imaging, so the 3.5% should not be read across to someone with no symptoms who booked a scan themselves. What it establishes is that a zero in someone who is having symptoms is a reason to bring it up, not a reason to set the symptoms aside.

We are not going to tell you what to take. You will find sites that turn a score into a drug recommendation. We are a directory, we have never met you, and that is your clinician’s call.

Who the scan is for

Calcium scoring is used selectively, when a clinician needs more information to make a prevention decision. The 2019 ACC/AHA primary prevention guideline describes it as “not intended as a ‘screening’ test for all but rather may be used as a decision aid in select adults to facilitate the clinician-patient risk discussion.” In that guideline, the selected adults are those at intermediate or selected borderline ten-year risk for whom a preventive treatment decision is otherwise uncertain (PMC7734661).

Announcing the 2026 ACC/AHA dyslipidemia guideline, the ACC and AHA said a calcium scan “is recommended for men age 40 and older and women age 45 and older with borderline or intermediate 10-year risk of heart attack or stroke if knowing CAC will help with the decision to prescribe a statin or not” (ACC/AHA news release, 13 March 2026). That guideline retired and replaced the 2018 cholesterol guideline that most pages on this subject still cite.

The other half of the picture

The US Preventive Services Task Force has never issued a recommendation for or against calcium scoring. Its current statement, from 2018, is an “I statement”: the Task Force concluded that “the current evidence is insufficient to assess the balance of benefits and harms of adding the ABI, hsCRP level, or CAC score to traditional risk assessment for CVD in asymptomatic adults to prevent CVD events.” It found that adding a calcium score produced “small improvements in discrimination and reclassification. However, the clinical meaning of these changes is largely unknown.” The harms it listed for calcium scoring specifically were radiation exposure and incidental findings on the CT that can lead to further testing (JAMA, 2018, PMID 29998297).

An I statement means the evidence was judged insufficient to weigh benefits against harms. It is not a finding that the test does not work, and it is not advice against having one. The Task Force’s topic “Enhanced Risk Assessment for Cardiovascular Disease: Coronary Artery Calcium Scoring” is listed as an update in progress; it reached the final research plan stage in September 2024 and no draft or final recommendation has been published, so the 2018 statement is still the Task Force’s current position.

Two respected bodies reach different conclusions about the same test, and both are stated accurately above. We sell nothing on either side of that.

Scanning again

There is no calendar rule, and anyone who gives you one has left out the condition that makes it true. The interval depends on your score, your other risk factors, and above all on whether a new number would change a decision.

For scores in the low positive range, the 2019 ACC/AHA primary prevention guideline says — in its supporting text rather than as a numbered recommendation — that for people with a score of 1 to 99 who are not on treatment, “repeat coronary artery calcium measurement in 5 years may have some value, but data are limited” (PMC7734661). The more specific three-to-five-year figure that circulates online comes from a National Lipid Association scientific statement rather than a guideline, which grades it Class 2b — its weakest actionable grade — and conditions it on the repeat result being able to change a treatment decision (Orringer CE, et al., Journal of Clinical Lipidology, 2021).

A repeat scan is not a report card on your treatment. Calcium scores tend to rise over time, and some treatments can make existing plaque denser — which pushes the score up even as the plaque becomes more stable. The change between two scans therefore does not reliably tell you whether treatment is working, in either direction. Routine repeat scanning to monitor treatment is not recommended (Sabouret P, et al., Frontiers in Radiology, 2026; Dzaye O, Blaha MJ, Razavi AC, American Journal of Preventive Cardiology, 2026, PMC13261271; mechanism described in Puri R, et al., JACC, 2015, an intravascular-ultrasound study in people with established coronary disease).

Scores rise on their own, too. In MESA, participants who already had coronary calcium saw it increase by a median of about 14 Agatston units a year in women and 21 in men, and about 6.6% of people per year developed detectable calcium for the first time (Kronmal RA, et al., Circulation, 2007, PMID 17502571).

A repeat scan also means more radiation. In a survey of 6,631 calcium scans at 742 imaging centers across 101 countries, the median effective dose was about 1.2 mSv, with half of scans falling between 0.7 and 2.2 mSv (Einstein AJ, et al., JAMA, 2026, PMC12936970). Dose depends on the scanner, the protocol and the patient, so it is a fair thing to ask an imaging center about before you book.

Before booking

Discuss whether testing would help you. Follow the imaging center’s preparation instructions; restrictions on food, caffeine and smoking may apply. See ACR/RSNA preparation guidance, and what a scan costs at the facilities we track.

Find a scan near you

Where facilities are listed

State and metro pages list imaging centers and hospitals where we track a coronary calcium CT (CPT 75571). A self-pay price is shown where we have one. Confirm the price, what it includes, and whether you need an order with the facility before you book. Nothing on those pages is a recommendation to have the scan.

States

States where we list at least one facility.

Metro areas with the most listings

Ranked by how many facilities we list in each Census metro area.

Browse every state and metro area. Search by ZIP code.

Sources

All sources accessed 17 September 2026.

This is general education, not medical advice, and no clinician has reviewed it. A calcium score is one data point. What yours means is a conversation with a licensed clinician who knows your history.

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